Forming size for glass fibers and resulting product

ABSTRACT

A method of producing an improved sized glass fiber strand suitable for plastisol coating is shown wherein glass fiber strand is treated with a starch based forming size comprising a starch, the salt of a polyamino-functional polyamide resin and a carboxylic acid, a wax and a fatty triglyceride. The novel sized strands produced are particularly adapted for further coating with a resinous material, preferably a plastisol resin, to provide glass fiber strands useful for the fabrication of insect screening and filtration fabrics.

Muted States Patent 1 1 1 3,869,308 Graham Mar. 4, 1975 [54] FORMINGSIZE FOR GLASS FIBERS AND 3 6l5,3ll 10/1971 lgnatius 65/3 RESULTINGPRODUCT 3.664,855 5/l972 Morrison et a]. 65/3 X 3.676095 7/1972 Stalegor. 65/3 [75] Inventor: Roy R. Graham, Lexington, NC. [73] Assignee: PPGIndustries, Inc., Pittsburgh, Pa. U' y Attorney, Agent, or Firm-RobertDCMiijlStffi [22] Filed: Apr. 27, 1973 [21] Appl. No.: 355,238 ABSTRACTA method of producing an improved sized glass fiber 5 u 17 I 1 7 2 Gstrand suitable for plastisol coating is shown wherein ii} iii; 8?.......f??.?ff..?if... $02155)? glass fiber is with a based form- [58]Field of Search 65/3; 117/126 GB 126 GO ing size comprising a starch,the salt of a polyaminofunctional polyamide resin and a carboxyltc acid,a [56] References Cited wax and a fatty triglyceride. The novel sizedstrands produced are particularly adapted for further coating UNITEDSTATES PATENTS with a resinous material, preferably a plastisol resin,to 2 7/1961 Gagno" a1 117/126 GO X provide glass fiber strands usefulfor the fabrication of gfiig i g g 23? i2 insect screening andfiltration fabrics. 33472.682 10/1969 Rammel et al 65/3 x 14 Claims, NoDrawings FORMING SIZE F OR GLASS FIBERS AND RESULTING PRODUCTDESCRIPTION OF THE PRIOR ART Glass fiber strands are composed of amultitude of fine glass filaments which are formed by being drawn at ahigh rate of speed from molten cones of glass located at a bushing suchas is shown in US. Pat. No. 2,133,238. During formation the filamentsarecoated while moving at a speed on the order of 5,000 to 20,000 feet perminute with a size which contains ingredients to give strand formed fromthe sized filaments integrity and workability for any standard textileor reinforcement use. After the glass filaments are formed and coated,they are drawn together by a gathering shoe into one or more glass fiberstrands. The drawing of the filaments from the bushing is effected bythe use of a winder, said winder being also used to accumulate the glassfiber strands on a forming package. If a stand so produced does not haveproper integrity, fuzzing occurs during these operations and eventuallythe strand breaks. Sizes typically contain a lubricant for the filamentsto prevent the destruction of strands during formation caused byabrasion of the individual filaments against each other or against glassfiber handling equipment.

Yarn or twisted strand (single end on bobbin) is made according toconventional textile twisting techniques by removing strand from formingpackages and winding them on a twist frame and collecting them on abobbin.

During the gathering and twisting operations, the glass strands aresubjected to pressure from the apparatus involved in the forming,twisting and gathering operations. Further, strands are often subjectedto pressure from other strands being wound on top of each other. Thispressure tends to cause the strands to fiatten rather than to form across-sectional circular configuration. This flattening is particularlydisadvantageous when strands or yarn are to be coated with a plastisolresin as single strands useful for insect screening, filtration fabricsand like purposes.

The process for producing fiber reinforced screening such as used forinsect screening, filtration fabrics and like purposes entails pouringthe molten plastisol resin onto a straight twisted strand or yarn anddrawing said coated strand through a circular die thus forming a singlecylindrical plastisol coated strand. A multiplicity of said strands arethen woven in a crosshatched pattern and fused at their intersection toform screening or fab- NC.

The manufacturers of this screening encounter difficulty in uniformlycoating glass fiber strands due to the cross-sectional flattening causedby the pressure exerted on the strands in the forming, gathering andtwisting operations used to produce strand. Such lack of uniform coatingresults in uncoated areas on the twisted strand or yarn, necessarilyexposing the fiber glass substrate thus inducing poor weatheringcharacteristics to the finished product. Hence there has beenencountered great difficulty in arriving at a proper sizing agent forfiber glass strand or yarn to be used for screening applications.

SUMMARY OF THE INVENTION Thus, in accordance with this invention amethod of sizing glass fibers which enables the glass fibers to beprocessed without breaking, without fuzzing and with generally goodhandling characteristics during forming is provided. Further the instantinvention provides sized fiber glass strand which is readily capable ofbeing uniformly coated with resinous materials and more particularlywith plastisol resins. Still further, this invention produces a sizingcomposition with the above properties which can be deposited out ofwater, hence obviating the use of organic solvents which present fireand physiological toxicity hazards.

Thus, in accordance with the practice of this invention, glass fiberstrands are treated during their formation with an aqueous size solutionwhose solids comprise 28 percent to percent by weight of a starch, 4percent to 52 percent by weight of the salt of a polyamino-functionalpolyamide resin and a carboxylic acid having 1 to 5 carbon atoms, 5 to25 percent by weight of a wax and 9 percent to 77 percent by weight of afatty triglyceride. The aqueous size used in accordance with the instantinvention has a viscosity which is suitable for glass fiber strandforming sizes. The size of the instant invention further permitsadequate pickup of size by the glass strand, provides good glass strandintegrity and prevents the destruction of glass strand by abrasion ofthe individual fibers against each other during forming operations.

The starch constituent of the size of the instant invention isincorporated to bind the fibers together into a strand in order that thestrand will have enough integrity to withstand the winding and twistingoperations encountered in processing strand. The starch constituent canbe any starch from the commercially available starches such as thosederived. from corn, potato, wheat, sago, tapioca and arrowroot and whichhas been modified by crosslinking or other means, such as distarchphosphates and the like. Also a high amylose unmodified starch may beused.

The salt of the polyamino-functional polyamide resin and carboxylic acidis formed by the addition of said carboxlic acid to saidpolyamino-functional polyamide resin. The polyamino-functional polyamideresin can be any such resin but preferably is one which has an aminevalue between and 400. These resins are formed normally by thecondensation reaction of a polycarboxylic acid such as a dimerized ortrimerized fatty acid and a polyamine such as tetraethylene pentamine,ethylene triamine, diethylene triamine, diethylene tetramine and thelike. The carboxylic acid constituent of the aforementioned salt ischosen from the group of organic carboxylic acid having 1 to 5 carbonatoms, such as formic acid, acetic acid, acrylic acid, methacrylic acid,butyric acid, chloroacetic acid, pentanoic acid or the like. Thehypothesized function of the polyamino salt is to provide the strandwith internal lubricity in order that the individual fibers do notabrade each other and break causing fuzzing and reduction in tensilestrength of the individual strand during processing. The polyamino saltin conjunction with the starch provides the proper internal lubricityand internal integrity required to allow the strand to be uniformlycoated with resinous materials for use as coated fiber glass strands.

The wax component of the sizing composition of this invention can be anysuitable wax selected from the group consisting essentially of vegetablewaxes such as Carnauba, Japan, bayberry, candelilla and the like, animalwaxes such as beeswax, Chinese wax, hydrogenated sperm oil wax and thelike; mineral waxes such as ozocerite, montan, ceresin and the like; andsynthetic' waxes such as polyethylenes, polyethylene glycols,polyethylene esters, chloronapthalines, sorbitols,polychlorotrifluoroethylene, microcyrstalline, paraffin and the like.The hypothesized function of the wax is to act as an external lubricantfor the fiber glass strand, allowing the strand to endure the abrasioncaused by strands to adhere to the resinous coating which will beapplied to the strands thus imparting improved moisture resistance to afinished product. Coupling agents which may be used in the aqueous sizecompositions in the practice of this invention include silane andsiloxane materials. For example, hydrolyzable vinyl, allyl, betachloropropyl, phenyl, thio-alkyl, thio-alkaryl, amino-alkyl, methacrylato, epoxy and mercapto silanes, their hydrolysis products andpolymers of the hydrolysis products and polymers of the hydrolysisproducts and mixtures of any of these are suitable for such use. Some ofthe silanes are disclosed in U.S. Pat. Nos.

3,207,623 and 3,211,684, the disclosures of which are incorporatedherein by reference.

Another class of coupling agents which has been found to be useful arethe basic (hydroxy containing) metal salts of a strong mineral acid,such as, for example, a basic chromium chloride, basic chromium sulfate,etc. These compounds are ones having a trivalent metal ion selected fromthe group consisting of chromium, cobalt, nickel, copper and lead, atleast one hydroxyl group attached to the metal, and at least one anionof a strong mineral acid attached to the metal (as well as coordinatecomplexes of these compounds and mixtures thereof).

Another type of coupling agent which may be used in the practice of thisinvention is a complex compound of the Werner type in which a trivalentnuclear atom,

such as chromium, is coordinated with an organic acid such a methacrylicacid, i.e., a methacrylic acid complex of chromic chloride. Such agentsare described in U.S. Pat. No. 2,611,718. Other Werner type couplingagents having vinyl alkyl amino, epoxy, mercapto, thioalkyl,thio-alkaryl, and phenyl groups are suitable for incorporation in thesize of the invention. Mixtures of two or more of any of these couplingagents may be used.

In addition, if desired, other known fiber glass lubricants can be addedto the primary components of the invention such as alkyl imidazolinederivatives which includes compounds of the class n-alkyl N-amidoalkylimidazolines which may be formed by causing fatty acids to react withpolyalkylene polyamines under conditions which produce ring closure. Thereaction of tetraethylene pentamine with stearic acid is exemplary ofsuch reaction. These imidazolines are described more fully in U.S. Pat.No. 2,200,815. Other suitable imidaz olines are described in U.S. Pat.Nos. 2,267,965, 2,268,273 and 2,355,837.

The above alkyl imidazoline derivative may be used in combination withor replaced-by a quaternary pyridinium compound which may be representedby the general formula:

wherein X is an anion; R is an organic group containing from one to 30carbon atoms selected from the group consisting of alykl, arylalkyl,aryl, alkenyl and acyl; and R R R R and R are each members selected fromthe group consisting of hydrogen, alkyl, aryl. arylalkyl. heterocyclic,halogen, alkenyl, carboxylic, alkoxy. ketonic, amido and substitutedamido. Thus, the anionic group X may be, for example, chloro, fluoro,iodo, bromo, hydroxyl, nitrate, sulfate, phosphate, etc. The group R maybe, for example, methyl, ethyl, butyl, hexyl, lauryl, oleyl, benzyl,phenyl, acetyl, propionyl, benzoyl, etc. The groups R R R R and R maybe, for example, methyl, ethyl, propyl, cyclohexyl, furyl, pyrryl,benzyl, phenyl, chloro, bromo, iodo, fluoro, oleyl, methoxy, acetoxy,benzoxy, acetonyl, acetamido, etc. These compounds are prepared inaccordance with methods common in the art by the quaternization of thecorresponding pyridine bases such as, pyridine, niacin, nicotin-amide,nicotine, nicotyrine, nikethamide, 2-benzylpyridine,3,5-dibromopyridine, 4- chloropyridine, 3-ethylpyridine,4-methoxypyridine, 3-phenylpyridine, 2-picoline, 3-picoline, 4-picoline,2-picoline-4,6-dicarboxylic acid, 2,4-lutidine, 2,6- lutidine,3,4-lutidine, 2,4-pyridine dicarboxylic acid, 4-ethyl-3-methylpyridine,3-ethyl-4-methylpyridine, 2,4,6-trimethylpyridine, etc.; with forexample, an alkyl halide.

The size utilized in accordance with the instant invention may alsoinclude a wetting agent. The wetting agent is preferably cationic ornon-ionic and it may also serve as an additional lubricant. Any materialcan be used which is conventionally known to be useful as such and whichwill reduce the surface tension of the aqueous size so that it is about25 to 35 dynes per square centimeter.

The total solids (non-aqueous) content of the aqueous size of theinvention is about 2 to 20 percent by weight of the sizing solution,preferably about 3 to 10 percent by weight of the sizing solution. Inall events the total solids should be adjusted to a level whereby theviscosity of the sizing solution is acceptable for application to theglass filaments, i.e., 10 to 50 cps. at 60C.

DESCRIPTION OF PREFERRED EMBODIMENTS The following example isillustrative of one method of practicing the instant invention.

The size applied to the fiber glass strand in accordance with thisinvention was composed of the ingredients listed in Table l.

Table l Ingredients Difilarch phosphate Paraffin wax Hydrogenated cornoil Polyoxyethylunu l5) Sorhitan Mnnoolcate (emulsifying agent) 5vcation Xtalkyl substituted imidaloline derivative. Onyx Chemical Co.)'1. ()ctylphenoxy lethylencoxyl ethanol Lardsurfactant) 7. Biomet 6o(biocide: hist tri-n-hutyltinl oxide and N-ulkyl (C, dimcthyl benzylammonium chloride) 8. (iamma-mcthacryloxy propytrimethoxy silane Aceticacid Vcrsamide I40 (General Mills; polyaminofunctional polyamide resin.amine value 370-400) I. Acetic acid 2. Water Parts by Weight (grams)Sufficient to make 10 gals. of size solution a solids 5.40 r 0.20% (1H5.x 2 0.:

An aqueous size was prepared as follows:

The starch heated to 225i'2F. and cooled to below 212F., was mixed withan oil and water emulsion of the paraffin wax, the hydrogenated corn oiland the polyoxyethylene (5) sorbitan monooleate; such emulsion formed byagitating the above ingredients with an Eppenbach agitator while addingenough water to emulsify; the cation X, after being dissolved insufficient water to form a homogeneous dispersion, is added to the abovestarch containing emulsion. The Biomet 66 and the octylphenoxy(ethyleneoxy) ethanol are then added to the mixture. Thegamma-methacryloxypropyltrimethoxy silane is added to the mixture afterhydrolysis with 2.5 grams of acetic acid in water solution. TheVersamide 140 is reacted with the 52 grams of acetic acid in watersolution to form a salt; the sizing solution is completed by theaddition of the salt solution and dilution to a total volume of 10gallons. During the entire procedure for combining the aboveingredients, agitation is employed to effect a homogeneous mixture.

The size of Table I prepared as described above is then applied toindividual glass fibers as they are drawn from orifices in anelectrically heated, platinum alloy bushing containing molten glass toform filaments of 0.00036 inch in diameter. The sizes are applied to thefilaments prior to the time they are grouped together to form a strandcontaining 200 filaments, by means of a roller applicator which ispartially submerged in the sizing solution contained in a reservoir.Such an applicator is shown in more detail in US. Pat. No. 2,728,972.The fibers are then grouped into strands by a gathering shoe and woundon a forming package rotating at approximately 4,420 rpm to produce astrand travel speed of approximately 14,000 feet per minute.

The glass fiber strands wound on the forming package are then dried.This may be done by any number of known methods sufficient to reduce themoisture After the strands are dried, they may be twisted byconventional tehcniques to form twisted strands (single end on bobbin)and are then ready for use in a coating operation. The single twistedstrand or yarn may be then coated with a resinous material, particularlya plastisol resin by adequate known techniques to form a cylindricalsingle coated strand suitable for fabrication into insect screening.

A plastisol resin is a dispersion of a high polymer in a non-volatilemedia. Virtually any high polymer can be used as the dispersed phase ina plastisol resin, however, preferentially the polymers used arehomopolymers of vinyl halides such as polyvinyl chloride, polyvinylfluoride and the like, and interpolymers of the vinyl halides such ascopolymers of vinyl chloride and diethy maleate, copolymers of vinylchloride and vinyl fluoride and the like. The resinous component, whichis ofa fine particle size (0.05 to 1.0 micron), has a preferred fusionpoint of less than 400F., such fusion point being desirable in orderthat decomposition of the polymer does not occur and. that thedispersing media remain non-volatile during the processing.

The non-volatile dispersing media is known in the art as a plasticizer.Such plasticizers can be of the chemical composition of esters such asdibutyl phthalate, di-2- ethylhexyl phthalate and the like; ketones suchas ethyl-O-benzoyl benzoate and the like; amides such as N- diethylstearamide, dibutyl stearamide and the like; and other similarcompounds.'The requisites of a plasticizer are that they are compatiblewith the film former, have a slight solvent action on the film former,are low in vapor pressure or volatility from the film, and possess otherdesirable coating and processing properties.

The twisted strands prepared as above described are coated with aplastisol coating utilizing conventional coating techniques. It is foundthat the coated strand has good inherent strength and a coating which isuniform and continuous. While certain fiber diameter and filament countsper strand are used in the above example, it will be obvious that otherfilaments and other strand compositions may be employed withoutdeparting from the spirit of the invention.

Although the present invention has been described with respect tospecific details of certain embodiments thereof, it is not intended thatsuch details act as limitations upon the scope of the invention insofaras set forth in the accompanying claims.

I claim:

1. A method of forming an improved, sized glass fiber strand suitablefor coating with a resinous material comprising:

drawing glass streams through orifices in a bushing to form individualglass fibers;

moving the fibers away from the bushing at a high rate of speed andforming then into a strand;

applying to the fibers while they are moving at this speed and beforethey are formed into strand a starch based aqueous sizing solution andnon-aqueous components thereof consisting essentially of 28 percent to75 percent by weight of a starch; 4 percent to 52 percent by weight ofthe salt of a polyamino functional polyamide resin, saidpolyaminofunctional polyamide resin salt being formed from thecondensation reaction product of a polycarboxcylic acid and a polyamine,said polyamine having greater than 2 amine groups per molecule, and acarboxcylic acid having 1 to carbon atoms; 5 to 25 percent by weight ofa wax from the group consisting of animal waxes, vegetable waxes,mineral waxes and synthetic waxes; and 9 percent to 77 percent by weightof a fatty triglyceride; and collecting the glass strands so produced.

2 The method of claim 1 wherein the size contains 1.5 percent to 20percent by weight of a coupling agent.

3. The method of claim 1 wherein the fatty triglyceride is hydrogenatedcorn oil.

4. The method of claim 1 wherein the starch is distarch phosphate.

5. The method of claim 1 wherein the carboxylic acid is acetic acid.

6. The method of claim 1 wherein the wax is paraffin wax.

7. The method of claim 1 wherein the size contains 10 to 45 percent byweight of an alkyl imidazoline.

8. An improved glass fiber strand suitable for the application of resinthereto and having disposed on the glass fibers an amount from about0.80 percent to about 2.5 percent by weight of the glass, the driedresidue of an aqueous size consisting essentially of 28 percent to 75percent by weight of a starch; 4 percent to 52 percent by weight of thesalt of a polyaminofunctional polyamide resin, said polyaminofunctionalpolyamide resin salt being formed from the condensation reaction productof a polycarboxcylic acid and a polyamine, said polyamine having greaterthan 2 amino groups per molecule and the carboxcylic acid having 1 to 5carbon atoms; 5 to 25 percent by weight of a wax from the groupconsisting of animal waxes, vegetable waxes, mineral waxes and syntheticwaxes and 9 percent to 77 percent by weight of a fatty triglyceride.

9. The strand of claim 8 wherein the dried residue on the strandcontains 1.5 percent to percent by weight of a coupling agent.

10 to 45 percent by weight of an alkyl imidazoline.

1. A method of forming an improved, sized glass fiber strand suitablefor coating with a resinous material comprising: drawing glass streamsthrough orifices in a bushing to form individual glass fibers; movingthe fibers away from the bushing at a high rate of speed and formingthen into a strand; applying to the fibers while they are moving at thisspeed and before they are formed into strand a starch based aqueoussizing solution and non-aqueous components thereof consistingessentially of 28 percent to 75 percent by weight of a starch; 4 percentto 52 percent by weight of the salt of a polyamino functional polyamideresin, said polyaminofunctional polyamide resin salt being formed fromthe condensation reaction product of a polycarboxcylic acid and apolyamine, said polyamine having greater than 2 amine groups permolecule, and a carboxcylic acid having 1 to 5 carbon atoms; 5 to 25percent by weight of a wax from the group consisting of animal waxes,vegetable waxes, mineral waxes and synthetic waxes; and 9 percent to 77percent by weight of a fatty triglyceride; and collecting the glassstrands so produced.
 2. The method of claim 1 wherein the size contains1.5 percent to 20 percent by weight of a coupling agent.
 3. The methodof claim 1 wherein the fatty triglyceride is hydrogenated corn oil. 4.The method of claim 1 wherein the starch is distarch phosphate.
 5. Themethod of claim 1 wherein the carboxylic acid is acetic acid.
 6. Themethod of claim 1 wherein the wax is paraffin wax.
 7. The method ofclaim 1 wherein the size contains 10 to 45 percent by weight of an alkylimidazoline.
 8. AN IMPROVED GLASS FIBER STRAND SUITABLE FOR THEAPPLICATION OF RESIN THERETO AND HAVING DISPOSED ON THE GLASS FIBERS ANAMOUNT FROM ABOUT 0.80 PERCENT TO ABOUT 2.5 PERCENT BY WEIGHT OF THEGLASS, THE DRIED RESIDUE OF AN AQUEOUS SIZE CONSISTING ESSENTIALLY OF 28PERCENT TO 75 PERCENT BY WEIGHT OF A STARCH; 4 PERCENT TO 52 PERCENT BYWEIGHT OF THE SALT OF A POLYAMINOFUNCTIONAL POLYAMIDE RESIN, SAIDPOLYAMINOFUNCTIONAL POLYAMIDE RESIN SALT BEING FORMED FROM THECONDENSATION REACTION PRODUCT OF A POLYCARBOXYCLIC ACID AND A POLYAMINE,SAID POLYAMINE HAVING GREATER THAN 2 AMINO GROUPS PER MOLECULE AND THECARBOXYCLIC ACID HAVING 1 TO 5 CARBON ATOMS; 5 TO 25 PERCENT BY WEIGHTOF A WAX FROM THE GROUP CONSISTING OF ANIMAL WAXES, VEGETABLE WAXES,MINERAL WAXES AND SYNTHETIC WAXES AND 9 PERCENT TO 77 PERCENT BY WEIGHTOF A FATTY TRIGLYCERIDE.
 9. The strand of claim 8 wherein the driedresidue on the strand contains 1.5 percent to 20 percent by weight of acoupling agent.
 10. The strand of claim 9 wherein the coupling agent isgammamethacryloxypropyltrimethoxy silane.
 11. The strand of claim 8wherein the fatty triglyceride is hydrogenated corn oil.
 12. The strandof claim 8 wherein the starch is distarch phosphate.
 13. The strand ofclaim 8 wherein the carboxylic acid is acetic acid.
 14. The strand ofclaim 8 wherein the size contains 10 to 45 percent by weight of an alkylimidazoline.